User-input functions for data sequences in polishing endpoint detection

A computer program product, tangibly embodied in a non-transitory machine readable storage device, comprising instructions to cause a processor to:

• receive input, in a computer system coupled to a polishing system and configured to control the polishing system, from a user of the polishing system through a graphical user interface selecting a function, the function including at least one parameter that can be varied;
• receive measurements of a substrate from an in-situ monitoring system during polishing;
• generate a sequence of values from the measurements from the in-situ monitoring system;
• fit the function to the sequence of values, the fitting including determining a value of the at least one parameter that provides a best fit of the function to the sequence of values;
• determine a projected time at which the function equals a target value;
• and
• determine at least one of a polishing endpoint or an adjustment for a polishing rate based on the projected time.

A chemical mechanical polishing system, comprising:

• a platen to support a polishing pad;
• a carrier head to hold a substrate in contact with the polishing pad;
• a motor to generate motion between the platen and the carrier head;
• an in-situ monitoring system to generate measurements of the substrate during polishing;
• and
• a controller configured to receive input from a user of the polishing system through a graphical user interface selecting a function, the function including at least one parameter that can be varied, receive the measurements from the in-situ monitoring system, generate a sequence of values from the measurements from the in-situ monitoring system, fit the function to the sequence of values, the fitting including determining a value of the at least one parameter that provides a best fit of the function to the sequence of values, determine a projected time at which the function equals a target value, and determine at least one of a polishing endpoint or an adjustment for a polishing rate based on the projected time.